Those who sponsored this view talked hopefully about shortcuts through higher dimensions, lines that were straighter than straight, and hyperspacial connectivity. They were fond of using an expressive phrase coined by a Princeton mathematician of the last century: "Wormholes in space." Critics who suggested that these ideas were too fantastic to be taken seriously were reminded of Niels Bohr's "Your theory is crazy – but not crazy enough to be true."

If there was disputation among the physicists, it was nothing compared with that among the biologists, when they discussed the hoary old problem: "What would intelligent extraterrestrials look like?" They divided themselves into two opposing camps – one arguing that such creatures must be humanoid, the other equally convinced that "they" would look nothing like men.

Settling for the first answer were those who believed that the design of two legs, two arms, and main sense organs at the highest point, was so basic and so sensible that it was hard to think of a better one. Of course, there would be minor differences like six fingers instead of five, oddly colored skin or hair, and peculiar facial arrangements; but most intelligent extraterrestrials – usually abbreviated to E.T.'s – would be so similar to Man that they might not be glanced at twice in poor lighting, or from a distance.

This anthropomorphic thinking was ridiculed by another group of biologists, true products of the Space Age who felt themselves free from the prejudices of the past. They pointed out that the human body was the result of millions of evolutionary choices, made by chance over eons of time. At any one of these countless moments of decision, the genetic dice might have fallen differently, perhaps with better results. For the human body was a bizarre piece of improvisation, full of organs that had been diverted from one function to another, not always very successfully – and even containing discarded items, like the appendix, that were now worse than useless.

There were other thinkers, Bowman also found, who held even more exotic views. They did not believe that really advanced beings would possess organic bodies at all. Sooner or later, as their scientific knowledge progressed, they would get rid of the fragile, disease-and-accident-prone homes that Nature had given them, and which doomed them to inevitable death. They would replace their natural bodies as they wore out – or perhaps even before that – by constructions of metal and plastic, and would thus achieve immortality. The brain might linger for a little while as the last remnant of the organic body, directing its mechanical limbs and observing the universe through its electronic senses – senses far finer and subtler than those that blind evolution could ever develop.

Even on Earth, the first steps in this direction had been taken. There were millions of men, doomed in earlier ages, who now lived active and happy lives thanks to artificial limbs, kidneys, lungs, and hearts. To this process there could be only one conclusion – however far off it might be.

And eventually even the brain might go. As the seat of consciousness, It was not essential; the development of electronic intelligence had proved that. The conflict between mind and machine might be resolved at last in the eternal truce of complete symbiosis.

But was even this the end? A few mystically inclined biologists went still further. They speculated, taking their cues from the beliefs of many religions, that mind would eventually free itself from matter. The robot body, like the flesh-and-blood one, would be no more than a stepping-stone to something which, long ago, men bad called "spirit."

And if there was anything beyond that, its name could only be God.

During the last three months, David Bowman had adapted himself so completely to his solitary way of life that he found it hard to remember any other existence. He had passed beyond despair and beyond hope, and had settled down to a largely automatic routine, punctuated by occasional crises as one or other of Discovery's systems showed signs of malfunctioning.

But he had not passed beyond curiosity, and sometimes the thought of the goal toward which he was driving filled him with a sense of exaltation – and a feeling of power. Not only was he the representative of the entire human race, but his actions during the next few weeks might determine its very future. In the whole of history, there had never been a situation quite like this. He was an Ambassador Extraordinary – Plenipotentiary – for all mankind.

That knowledge helped him in many subtle ways. He kept himself neat and tidy; no matter how tired he became, he never skipped a shave. Mission Control, he knew, was watching him closely for the first signs of any abnormal behavior; he was determined that it should watch in vain – at least, for any serious symptoms.

Bowman was aware of some changes in his behavior patterns; it would have been absurd to expect anything else in the circumstances. He could no longer tolerate silence; except when he was sleeping, or talking over the circuit to Earth, he kept the ship's sound system running at almost painful loudness.

At first, needing the companionship of the human voice, he had listened to classical plays – especially the works of Shaw, Ibsen, and Shakespeare – or poetry readings from Discovery's enormous library of recorded sounds. The problems they dealt with, however, seemed so remote, or so easily resolved with a little common sense, that after a while he lost patience with them.

So he switched to opera – usually in Italian or German, so that he was not distracted even by the minimal intellectual content that most operas contained. This phase lasted for two weeks before he realized that the sound of all these superbly trained voices was only exacerbating his loneliness. But what finally ended this cycle was Verdi's Requiem Mass, which he had never heard performed on Earth. The "Dies Irae," roaring with ominous appropriateness through the empty ship, left him completely shattered; and when the trumpets of Doomsday echoed from the heavens, he could endure no more.

Thereafter, he played only instrumental music. He started with the romantic composers, but shed them one by one as their emotional outpourings became too oppressive. Sibelius, Tchaikovsky, Berlioz, lasted a few weeks, Beethoven rather longer. He finally found peace, as so many others had done, in the abstract architecture of Bach, occasionally ornamented with Mozart.

And so Discovery drove on toward Saturn, as often as not pulsating with the cool music of the harpsichord, the frozen thoughts of a brain that had been dust for twice a hundred years.

Even from its present ten million miles, Saturn already appeared larger than the Moon as seen from Earth. To the naked eye it was a glorious spectacle; through the telescope, it was unbelievable.

The body of the planet might have been mistaken for Jupiter in one of his quieter moods. There were the same bands of cloud – though paler and less distinct than on that slightly larger world – and the same continent-sized disturbances moving slowly across the atmosphere. However, there was one striking difference between the two planets; even at a glance, it was obvious that Saturn was not spherical. It was so flattened at the poles that it sometimes gave the impression of slight deformity.

But the glory of the rings continually drew Bowman's eye away from the planet; in their complexity of detail, and delicacy of shading, they were a universe in themselves. In addition to the great main gap between the inner and outer rings, there were at least fifty other subdivisions or boundaries, where there were distinct changes in the brightness of the planet's gigantic halo. It was as if Saturn was surrounded by scores of concentric hoops, all touching each other, all so flat that they might have been cut from the thinnest possible paper. The system of the rings looked like some delicate work of art, or a fragile toy to be admired but never touched. By no effort of the will could Bowman really appreciate its true scale, and convince himself that the whole planet Earth, if set down here, would look like a ball bearing rolling round the rim of a dinner plate.